(1) An employee of a participating employer who becomes a member as provided in K.S.A. 74-4911 and amendments thereto, after completion of one year of continuous employment as therein provided may purchase participating service credit for such year of employment by making application therefor. Such application and payment may be made at any time after the employee becomes a member and continues to be employed by a participating employer. Any member of the system who has not retired may purchase, subject to the provisions of K.S.A. 74-49,123 and amendments thereto, such service credit by paying the then present value of the retirement benefits based on such service by means of a single lump-sum payment in the amount determined by the actuary using the member's attained age and the actuarial assumptions and tables currently in use by this retirement system. If an employee was employed before the participating employer's entry date and did not become a member until the first day of the month or the first day of the first payroll period, whichever is applicable, coinciding with or following the completion of one year continuous employment, the member may purchase, subject to the provisions of K.S.A. 74-49,123 and amendments thereto, participating service credit for the period from the participating employer's entry date until such member became a member by paying to the system the then present value of the retirement benefits based on such service by means of a single lump-sum payment in the amount determined by the actuary using the member's attained age and the actuarial assumptions and tables currently in use by this retirement system. Notwithstanding any other provision of this subsection, if an employee purchases such participating service credit within 12 months of such employee's membership in the system, such employee may purchase such participating service credit by making application therefor and paying to the system a lump-sum amount equivalent to 4% of the compensation paid to such member for personal services during such period. If an employee was employed for a partial year after the participating employer's entry date and did not become a member at that time, but became a member at a later date, the member may purchase, subject to the provisions of K.S.A. 74-49,123 and amendments thereto, participating service credit for such partial year of employment by paying the then present value of the retirement benefits based on such service by means of a single lump-sum payment in the amount determined by the actuary using the member's attained age and the actuarial assumptions and tables currently in use by this retirement system.